Ephesus is one of the best-preserved ancient cities in the world. It is near Selçuk, İzmir; allow a full day.
The Library of Celsus with its iconic façade is a photo stop. Walk the Great Theatre and Harbor Street. House of Virgin Mary and Temple of Artemis remains are also on the list.
You can hire a guide or audio guide at the entrance. Comfortable shoes and a hat are recommended for sun and walking.